A Further Comparison of Imagery and Vocalization Strategies in Children's Discrimination Learning.

Three experiments were conducted using fifth and sixth graders to determine the effectiveness of verbal and imaginal rehearsal strategies in children's discrimination learning. With verbal materials, imaging the referent of the correct item was more facilitative than vocalizing the correct item, as long as the imagery strategy was executed in the company of relevant motor activity. In fact, when children engaged in such a strategy, their verbal discrimination performance was virtually error free. No difference between the two strategies was found in pictorial discrimination learning, both resulting in performance very near ceiling. A possible interpretation of the results was provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Local secretion of corticotropin-releasing hormone by enterochromaffin cells in human colon

BACKGROUND/AIMS: Corticotropin-releasing hormone (CRH) is a regulator of the hypothalamic-pituitary-adrenal axis and a coordinator of the gastrointestinal response to stress. In addition to its central effects, CRH has peripheral effects on the immune system. CRH is present in several human tissues, such as the brain, spinal cord, adrenal medulla, lung, liver, peripheral blood leukocytes, as well as the gastrointestinal tract. The current study examined the local production of CRH in the normal human colon. METHODS: Normal human colonic tissues obtained by endoscopic biopsy were immunostained with anti-CRH and anti-5-hydroxytryptamine antibody and analyzed for CRH messenger (m)RNA by a reverse-transcribed polymerase chain reaction method and by in situ hybridization. RESULTS: Immunoreactive CRH and CRH mRNA were detected in the colonic mucosal cells in the neighborhood of the base of the crypts. The mucosal cells that expressed CRH mRNA also immunostained with anti-5-hydroxytryptamine antibody. CONCLUSIONS: Normal human colonic mucosal enterochromaffin cells produce CRH. CRH in the colonic mucosa may play a role in the modulation of the intestinal immune system and/or other gastrointestinal functions basally during stressful conditions.     

Characterization of Programmed-Waveform Pulsewidth Modulation

Programmed-waveform pulsewidth modulated (PWM) waveforms, applicable to ac-dc/dc-ac converters, are synthesized and analyzed in terms of several structural parameters. By invoking sensitivity studies and heuristics, optimal PWM structures are identified and contrasted. The results show total harmonic performance as a function of switching levels, waveform types, commutations per cycle, and filter bandpass.     

Twitter: An Underutilized Potential during Sudden Crises?

The widespread use of Twitter by citizens during sudden crises has convinced communications experts that governments should also actively use Twitter during crises. However, this position seems insufficiently empirically validated. In this article, we want to provide empirical building blocks for an informed approach to the use of Twitter by the government. To this end, we analyze the tweets posted by citizens and governments about the large‐scale fire in Moerdijk (2011), the Netherlands. The results show that by far, most tweets do not contain any new and relevant information for governments and that the tweets posted by governments got buried under an avalanche of citizen tweets. We may conclude that the Moerdijk case does not give rise to advocate a (more) active role of governments on Twitter during sudden crises.